Long-term cumulative associations of annual air pollution exposure and hospitalization with Parkinson’s Disease
Background: Parkinson’s Disease (PD) prevention and treatment are complicated because biological processes underlying PD may begin several years before diagnosis. Previous studies suggest that increased exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) air pollution increases PD morbidity. Methods: We analyzed data from 10,366,083 Medicare fee-for-service beneficiaries (age 65+) in the contiguous United States from 2000 to 2016. We defined “hospitalization with PD” as a beneficiary’s first hospitalization claim with diagnosis codes indicating PD. We linked 10-year exposure histories for PM2.5, NO2, and summer ozone (O3). In a discrete-time survival analysis, we fitted distributed lag models and estimated the lagged associations between air pollution and the odds of first hospitalization with PD. Results: Increased PM2.5 and NO2 exposure at least 4 years before hospitalization was associated with increased odds of hospitalization with PD. Accounting for nonlinearities in exposure-response and 10 years of continuous exposure to PM2.5 at the 90th versus the 0.5th percentile (i.e., 11.8 μg/m3 vs. 3.0 μg/m3), the odds ratio for hospitalization with PD was 1.634 (95% CI: 1.489, 1.792). Similarly, for 10 years of continuous exposure to NO2 at the 90th versus the 0.5th percentile (i.e., 31.7 ppb vs. 3.7 ppb), the odds ratio for hospitalization with PD was 1.474 (95% CI: 1.379, 1.575). Evidence of a relationship between O3 exposure and odds for hospitalization with PD was more limited. Conclusions: Air pollution at least 4 years before hospitalization may increase the odds of hospitalization with PD. Reducing air pollution exposure may have long-term effects on PD prevention.